In order to achieve short processing times of work pieces to be processed on a sewing machine, e.g. for the sewing of button holes on the front of the shirt it is advantageous to remove a finished work piece quickly from the sewing area and to feed it in a defined, precise manner into a stacker and to feed the next work piece into the sewing machine in a time overlap.
German publication 22 13 576 in International Class D05 B, group 23/00, describes a sewing automat having two continuously driven conveyor belts which are arranged parallel and at a distance with regard to one another, and which are arranged above a table top carrying the work pieces and which transport the work pieces in a continuous motion along the stitch formation area and away from the sewing machine. The conveyor belts also extend above a feeding table which can be moved from a low loading position to a high transfer position in which the conveyor belts can take over a placed and aligned work piece and feed it to the sewing machine.
The liftable and lowerable feeding table allows for overlapping operation, however, there is a danger that with thin and flexible work pieces the front edge of the work piece is caught in the joint between the table top and the feeding table and that it rolls up. Also, due to the continuous operation of the conveyor belts it is difficult to pass the work piece on to or take it from a stacker in a defined manner.
U.S. Pat. No. 43 80 205 in International Class D05 B, group 1/12 describes a work piece transport device for an overhand sewing machine arranged on a table top. The transport device has either one or two conveyor belts arranged parallel and at a distance with regard to one another, which are led over a drive disc arranged mounted fixedly in a bearing mounted fixedly and a deflection disc, which is arranged on an arm pivoting around a vertical and a horizontal axis and whose swivelled position can be fixed by means of two clamping screws. When no longer needed, the arm with the deflection disc is manually swivelled laterally from below the horizontally arranged presser foot carrying lever of the sewing machine and then it is swivelled upward into a resting position in which it is arrested. For the execution of a thread cutting process the holder for the bearings of the arm can be swivelled around the axis of the drive disc by means of a compressed-air pneumatic cylinder which results in a minor upward movement of the deflection disc.
The known workpiece transport device is adjusted to the design and the elevated position of the overhand sewing machine mounted to the table top and is unsuited for the removal of work pieces lying on a table top which is aligned with the work piece contact surface of the sewing machine. Furthermore, no measures were taken that allow an overlapping operation for the sewing and feeding of the next work piece and that guarantee a defined, precise transfer of a finished work piece to a stacker.